Bash script which replaces all non-ASCII characters with another character in filenames for all files and directories contained within the target directory.

replace_non_ascii.sh

#!/usr/bin/env bash

USAGE="$(basename "$0") [-h] [-d] [-e] target_dir 

Replaces all non-ASCII characters with another character in filenames
for all files and directories contained within the target directory.

where:
    -h, --help               Show this help text
    -d, --dry-run            Display the expected changes, but do not perform them. If
                             a file is in a directory that needs to be renamed, it will
                             be reported during a dry run.
    -e, --replace-with       Text which will replace non-ASCII characters. Default '_'.
"


REPLACE_WITH="_"
TARGET_DIR=""
while (( "$#" )); do
  case "$1" in
    -e|--replace-with)
      REPLACE_WITH=$2
      shift 2
      ;;
    -d|--dry-run)
      DRY_RUN=YES
      shift
      ;;
    -h|--help)
      SHOW_HELP=YES
      shift
      ;;
    -*|--*=) # unsupported flags
      echo "Error: Unsupported flag $1" >&2
      exit 1
      ;;
    *) # preserve positional arguments
      TARGET_DIR="$TARGET_DIR $1"
      shift
      ;;
  esac
done
set -- "$TARGET_DIR" # restore positional parameters

if [ "$SHOW_HELP" = "YES" ] || [ "$TARGET_DIR" = "" ]; then
  echo "$USAGE"
  exit 0
fi

if [ "$DRY_RUN" != "YES" ]; then
  echo "Replacing non-ASCII characters with '$REPLACE_WITH'"
  RENAME_CMD=' rename($_, $new);'
else
  echo "WARNING: Performing dry run, no file names will be changed"
fi
echo "-----------------"

do_replace() {
  FIND_TYPE=$1

  find $TARGET_DIR -type $FIND_TYPE -print0 | \
  perl -n0e '
    use open qw/:std :utf8/;
    $new = $_;
    if ($new =~ s/([\x{0001}-\x{001F}\x{E000}-\x{F8FF}\*"\\\|:\?<>])+/'"$REPLACE_WITH"'/g && $_ ne $new) {
      # trim off the null character
      $new = substr($new, 0, -1);
      # Trim whitespace
      $new =~ s/^\s+|\s+$//g ;
      print("Renaming \"$_\" to \"$new\"\n");
      if (-e $new) {
        print("** WARNING: Skipped rename, file already exists with new name\n");
      } else {
        '"$RENAME_CMD"'
      }
    }'
}

do_replace 'd'
do_replace 'f'